Ride height setting adjustment

With P2187 finally on the road after two years and registered in TX as of Friday, the drive out to the truck stop to weigh it for TX DMV made me think about the ride height (forutnately it was a pretty smooth road). Looks to me like the car is sitting a little less than 3.5" off the ground when eyeballing with a ruler, vs the roughly 4.5" the manual indicates. This makes it about 1.5-2" off the ground at the front of the oil pan. Way too low it seems to me.

What is the best process for raising the car a good inch all the way around without screwing up the handling (ie, seems to me I read on one of the threads that adjusting a rear effected the front and visa versa).

Thanx
Mark

Lift off ground, remove all four wheels, take initial measurements of lower spring perch, slightly loosen lock ring, twist up to desired height with a spanner wrench, re-tighten lock ring, repeat on other wheels. Will also help with bump steer. Makes for good practice safety wiring spinners. Remember to pull the safety wire in the "tightening" direction.

Mark,

Ditto what Rich said.

If you need to go up that far, you're going to need a four wheel full alignment (camber, caster, toe) afterwards. You'll definitely have major toe issues on the front, and likely also on the rear just for starters. You'll probably have camber out quite a bit as well. I use an 1/8th toe in on the front and rear, 0 camber rear, 1 neg front, and caster around 3.5. That works well on my car for primarily street driving.

The few hundred bucks it costs for a proper full alignment is well worth it.

Good luck!

You know I tried my hand at doing the alignment in my garage using tape measure and laser beam but the car handled bad at speed, took it to a alignment shop and after they adjusted to SPF specs it handled perfect all the way to 165 MPH. When the pro was doing the alignment, all the little red paint marks lined back up on the adjustment links. I guess SPF does all this before they leave the factory.

What oil pan did you use on your motor? I bought one from Dennis Olthoff which was used on the Roush motors. Got any pictures? I just took a picture of the bottom of my car, the oil pan is flush with the bottom.

muttsjet said:

...the car is sitting a little less than 3.5" off the ground when eyeballing with a ruler, vs the roughly 4.5" the manual indicates.

Click to expand...

I just noticed the same thing on mine when I loaded it into the trailer and the doors didn't clear the trailer wheel wells as I expected them to. Part of that is probably that you and I are running iron big blocks. But I don't think the weight difference between our mills and an iron block windsor should amount to a full inch (assuming the wheel rate is ~300 lb/in). Could the factory have assume an aluminum block Windsor?

Re: Ride height setting adjustment - Trig in Public

Point of departure using Superformance intial setup and 427SO/RBT installed:
- sitting at 3 inches off the ground in the rear
-- rear tires Yokohama AVID S/T 295/50/R15
- 3.5 inches off the ground in the front.
-- front tires Yokohama AVID T4 225/60/R15
- all tires at 17 psi

So, if the front is supposed to be 4.125-4.5 inches off the ground, and the rear is supposed to be 4.5-4.75 off the ground, here's what I did:
- couldn't find an agreed upon tire pressure on the forum so put them all at 26 psi (2600lb/100=26psi)
- since the "triangle" formed by the supension looked about 30-60-90
-- in the front I raised the coilover 1 inch (the hypotnuse), which should have raised the car vertically about .8 inch, and with a nomimal amount for the tire pressure (.125), front should have been at 4.425 inches INSTEAD 5.5 inches
-- in the rear I raised the coilover 1.7 inches (the hypotnuse), which should have raised the car vertically about 1.5 inche, and with a nomimal amount for the tire pressure (.125), rear should have been at 4.625 inches, INSTEAD ALSO 5.5 inches

So, is it a math problem, or does the tire pressure make a lot more difference than the .125 I allotted? What are folks running for tire pressure for street driving.

Standing by before I get back into the coilovers (by the way, the fronts were no problem raising the coilovers; the rears were a pain since I left them on the car; used spring compressors (tight fit) to compress rears to raised the coilovers).

Thanx
Mark

I just checked mine. Avon's on all 4 corners:

22 psi front
20.5 psi rear

Remember its light car...

Avons will save your life.

Mark,

Generally speaking, if you raise the position of the perch on the coilover by X amount then there's usually a multiple of X increase in ride height because of the length of the A-arm from its pivot on the chassis to the ball joint on the outboard end.

In other words, because the coilover is typically (not always, but usually) inboard of the ball joint on the upright, changes in the height setting of the coilover have an amplified effect at the outboard end of the A-arm. So, say you wanted to go up one inch in ride height then you would normally move the perch on the coilover less than an inch.

Helpful?

Cliffbeer2 said:

Mark,

Generally speaking, if you raise the position of the perch on the coilover by X amount then there's usually a multiple of X increase in ride height because of the length of the A-arm from its pivot on the chassis to the ball joint on the outboard end.

Click to expand...

Mark calculated 0.8 for this, and I got 0.75, so I think he's got that part figured out. My guess is that the car just needs to be rolled around and bounced to get that extra inch to settle out of the suspension. There's that old problem where with the car in the air the contact patches are closer together (laterally) so that when you drop it onto the ground it sits high until you roll it a bit and let the tires find the proper lateral position. At least, I hope that's what's going on....